FREE IMMUNOGLOBULIN LIGHT CHAIN SYNTHESIS BY HUMAN-FETAL LIVER AND CORD BLOOD-LYMPHOCYTES

Abstract

Ig synthesis by immature B lymphocytes from human fetal liver and cord blood was investigated. Seven of 15 preparations of fetal liver cells and 8 of 11 cord bloods synthesized Ig detectable by biosynthetic labeling. All cultures of fetal lymphocytes with detectable Ig synthesis secreted free Ig-chain. Two of these cases also synthesized free .mu. H-chain. Cord blood lymphocyte synthesis patterns were variable ranging from free L-chain as the only secreted Ig product to balanced synthesis of H- and L-chains. No cord blood cultures synthesized detectable free .mu. chains. Free Ig-L-chain synthesis appears to be associated with normal immature B lymphocytes. The results are discussed in relation to the B-cell differentiation pathway.